Feeding mechanism for sewing machines



April 20 1926. I 1,581,221 .J.-R. MOFFATT FEEDING MECHANISM FOK SEWINGMACHINES Filed July 14, 1921; 2 Sheets-Sheet 1 April 20,1926. 1,581,221

- J.. R. MOFFATT I FEEDING MECHANISM FOR, SEW IBG MACHINES Filed Jqly1.4 1921 I 2 Sheets-Sheet 2 Patented Apr. 20, 1926.

UNITED STATES JAMES R. Morr'A'r'r, or CHICAGO. ILLINOIS, Assienon 'roUnion SPECIAL MACHINE COMPANY, or CHICAGO, rumors, A ooaroaa'rron orILLINOIS.

FEEDING MECHANISM non snwme MACHINES.

Application filed July 14, 1921. Serial No. 484,665.

To all whom it may concern:

Be it known that 1, James R. Morra'rr, a citizen of the United States,residing at Chicago, in the county of-Cook, State of Illinois, haveinvented certain new and useful Improvements in Feeding Mechanisms forSewing Machines, of which the following is a description, referencebeing had to the accompanying drawing and to the figures of referencemarked thereon.

The invention relates to new and useful improvements in feedingmechanisms for sewing machines," and more particularly to a feedingmechanism for a sewing machine having a covering stitch formingmechanisin.

An object of the invention is to provide a feeding mechanism for amachine of the above type, which feeding mechanism in cludes fabricengaging and feeding sections which are capable of yielding relative toother fabric engaging and feeding sections to accommodate varyingconditions in the thickness of the seam.

A further object of the invention is to provide a feeding mechanism ofthe above character wherein the yielding sections are of substantiallythe same width as the covered seam formed by the stitching mech anismand located in rear of the needles.

A still further object of the invention is to provide a feedingmechanism of the above character wherein the throat plate in rear of theneedles is provided with a groove adapted to receive the increasedthickness in the seam due to overlapping fabricsections within thelimits of the stitching mechanism, and wherein the feeding dog forfeeding the material is provided with yielding fabric engaging surfacesadapted to engage the material pressing into said groove, and rigidfabric engaging surfaces disposed at each side of said groove andengaging the fabric at each side of the covering stitches.

These and other objects will in part be obvious and will in part behereinafter more fully disclosed.

In the drawings Figure 1 is a plan view of a portion of a sewing machineof the cylinder bed type having my improvements applied thereto; Fig. 2is a similarview withthe presser foot and other elements above the clothplate removed;

Fig. 3 is a sectional view on the line 3-3 of Fig. 2;

Fig. {i is a planview of my improved feed which is constructed so as toform a covered seam the edges of the fabric sections being eitherslightly overlapped or abutted and the fabric sections and a crossthread or threads above'the fabric sections. The overlapping of thefabric sections together with the cross threads form extra thickness inthe seam, that is the fabric sections are of greater thickness at theline where they are united than they are back from the covering seam.Considerable difliculty has been experienced in properly feeding thefabric sections owing to this increased thickness in the seam.The'present invention is directed particularly to a feeding mechanismwhereinthe fabric'sections not only in the region of the seam but ateach side thereof are firmly gripped and fed by the feeding mech-' anismnotwithstanding this increased thickness in the seam and even though thethickness in the team should vary by reason of cross seamsor the likeextending into the seam joining the fabric sections.

In carrying out the invention either the resser foot or the throat plateis provided with a groove in rear of the needles, and this groove is ofsufficient depth and width 'to receive the extra thickness of the seam.The feed dog is provided with rigid fabric engaging sections disposed atopposite sides of the groove and adapted to engage the respective fabricsections at each side of the covering seam. The feed dog is alsoprovided with'yielding fabric engaging sections oined by a plurality ofneedle threads con. nected by a looper thread or threads below locatedbetween the needles and between the I rigid fabric engaging sectionswhich are adapted to engage the fabric sections within the limits of thecovering seam. These yielding sections of the feed dog will engage thefabric sections even though they vary in thickness and will firmly gripthe same, and thus the fabric sections throughout the region of the seamand at each side thereof will be gripped and fed at each feedingoperation.

Referring more in detail to the drawings, I have shown the invention asapplied to a cylinder bed type of machine, such as shown in the patentgranted to Joseph Berger November 5, 1918, No. 1,283,639. In this typeof machine the material is fed off from the end of the arm. The worksupporting arm is indicated at 1, and said work supporting arm isprovided with a throat plate 2 on which the material rests duringstitching. Said throat plate is provided with needle openings 333through which the needles 4a4t pass. The needles are each provided witha thread and form needle thread loops which are joined on the upper faceof the fabric by a cross thread, indicated at in Fig. 7 of the drawings.In this figure the needle threads are indicated at a and theneedlethread loops beneath the fabric sections are connected by a looperthread I). The two fabric sections are indicated at F and F. Said fabricsections, as shown in Fig. 7 are overlapped and the overlapped portionsare disposed within the limits of the outer needles which form theneedle thread loops aa, hence these outer needle thread loops passthrough the respective fabric sections only, while the center needlethread loop passes through both of the fab- "ic sections.

The material is held on the work support by means of a presser foot 5,which presser foot is provided with a yielding section 6. Said presserfoot carries a stationary trimming blade 7 with which a movabletriniming blade 8 cooperates. The edges of the fabric sections areturned up, and then pass through the guiding slot at the forward end ofthe presser foot, are trimmed, and are then turned down into overlappedrelation for stitching, as more fully disclosed in said Berger patent.

The throat plate 2 is provided with a groove or recess 8. Said recess 8is located in rear of the opening 9 in the throat plate. The needleopenings 3 lead into the opening 9, and stitch forming fingers 10carried by the throat plate project into said opening 9. The recess 8 issubstantially the same width as the opening 9 and the opening 9 issubstantially the same width as the stitching mechanism, that is, thedistance between the outer faces of the outer needles. The main section5 of the presser footextends over the recess 8, and the rear end of therecess 8 is slightly in rear of the rear end of the presser foot. Theoverlapped edge portions of the fabric sections together with threadspass into the recess 8, as clearly shown in Fig. 6. The throat plate isprovided with slots 1111 at each side of the recess 8. Said throat plateis also provided with bars 12 between which are slots 12 which open intothe recess 8.

The feeding mechanism includes a feed dog 13, said feed dog 13 beingformed with a shank 14 which is provided with an elongated opening 15through which a suitable screw passes for securing the feed dog to thefeed bar. Said feed dog has main fabric engaging sections 16 and 17which are rigidly secured to the shank 1 1. Threaded into theflow-erface of the section 16 is a headed bolt 18, and threaded into the lowerface of the section 17 is a headed bolt 19. Mounted on these bolts 18and 19 is a cross head 20. Said cross head is provided with sleevesencircling the bolts. Coiled springs 21 encircle these sleeves and bearagainstt-he heads of the bolts and also against the cross head andoperate to yieldin ly lift the cross head. The cross head is providedwith fabric engaging sections 22 which extend through the slots 12.These fabric engaging sections 22 are provided with teeth similar to theteeth on the fabric engaging sections 16 and 17. The spring normallyraises the cross head until its upper face engages the lower face of thefeed bar sections 16 and 17, and when in this position the fabricengaging sections 22 are substantially on the same level as the mainfabric engaging sec tions 16 and 17. These fabric engaging section-s 22operate in the region of only and bear against the overlapped portionsof the fabric sections forming the seam.

It will readily be seen that said sections 22 will yield to correspondto varying thicknesses in the seam. The springs 21 are of sufficienttension so that these yielding sections 22 will engage the fabric firmlyand cooperate with the sections 16 and 17 in the feeding of the fabric.While the section 22 yields to correspond to the varying thicknesses inthe fabric at the lapped portion of the seam, said yielding section hasthe same longitudinal movement as the main section and will cooperatewith said main section in the feeding of the fabric a stitch length.This is accomplished, too, without disturbing the portion of the fabricengaged by the yielding section relative to the portion of the fabricengaged by the rigid sections of the feed dog. The fabric sections willbe engaged in rear of the needles and at each side of the needles, asthe sections 16 and 17, as clearly shown in Fig. 2, ext-end along sideof the needles as well as in rear thereof.

in auxiliary or differential feed dog may be used in conjunction withthe feed dog above described and will be located, of

the recess 8.

course, in front of the needles and in front of the fabric engagingsections 16 and 17. V'hile I have shown-the throat plate as providedwith a recess and the yielding sections as limited in their upwardmovement to a position level with the main fabric feeding sections, itwill be understood that the arrangement of the recess and of theyielding sections may be varied without departing from the spirit of theinvention as set forth in the appended claims, the essential featureconsisting in the providing of a clearance space for the seam and of theyielding sections of the feed dog which engage the seam within thelimits of the covering stitch forming mechanism.

Vi hile also I have shown the invention as applied to a feed-off-the-armcylinder type of the work support, from certain aspects of theinvention, my improved feeding mechanism may be used with afeednp-the-arm machine or a flat bed type of machine. It will also beapparent that while I have shown and described my improved feedingmechanism as especially adapted for feeding fabric sections which areoverlapped and joined by covering stitches, it will be understood thatthe sections may be abutted and joined by covering sitches instead ofoverlapped. Where a plurality of cross threads are used or a pluralityof lower threads, thus forming considerable thickness to the seam, myimproved feeding mechanism will readily take care of the extra thicknessand feed the fabric sections uniformly.

Having thus particularly described the invention, what is claimed as newis 1. The combination with a Work support and a presser foot; of afeeding mechanism including a feed dog having main rigid fabric engagingsections, and fabric engaging sections adapted to yield bodily andvertically to accommodate different thicknesses in material, saidyielding section having the same longitudinal movement as the main rigidsections.

2. The combination with a work support and a presser foot; of a feedingmechanism including main rigid fabric feeding sections, and fabricengaging sections disposed between said rigid fabric feeding sectionsand adapted to yield vertically to accommodate material of varyingthicknesses, said yielding section having the same longitudinal movementas the main rigid sections.

3. The combination with a work support, a plurality of needles, and apresser foot; of a feeding mechanism including yield vertically toaccommodate the overlapped edges of fabric sections being fed to theneedles. v

4. The combination of a work support, a throat plate carried thereby,said throat plate having needle openings formed therein, and a recess inrear of said needle openings of substantially the same width as thedistance between the outer needle openings, a plurality of needles, anda feeding mechanism including rigid fabric feeding sections at each sideof said recess and needles, and yielding fabric feeding sections adaptedto engage the "fabric sections passing through said recess. s

V 5. A feed dog for sewing machines comprising a supporting shank, mainrigid spaced fabric engaging sections carried thereby, fabric engagingsections located between said rigid fabric engaging sections, and meansfor supporting the fabric engaging section located between the rigidsections, whereby said central section can yield bodily and vertically,said yielding section being mounted upon the shank of the feed dog andhaving the same longitudinal movement as the main rigid sections of thefeed dog.

6. A feed dog for sewing machines comprising a supporting shank, spacedmain fabric engaging sections rigidly carried by said shank, fabricengaging sections located between said rigid sections, and means forsupporting said intermediate fabric engaging sections from said rigidfabric engaging sections whereby said intermediate fabric en gagingsection may yield vertically-to accommodate overlapped fabric sectionsbeing fed thereby, said yielding section having the same longitudinalmovement as the main.

fabric engaging sections.

7. A feed dog comprising a supporting shank, spaced rigid fabricengaging sections, headed bolts carried thereby, a cross head havingsleeves sliding on said bolts, springs surrounding said sleeves andengaging the cross head for raising the cross head, fabric engagingsections carried by the cross head and disposed intermediate the rigidfabric engaging sections.

In testimony whereof, I affix my signature.

JAMES R. MOFFATT.

